Module cluster_command 

Typed cluster command encoding for Raft log entries.

All commands written into the Raft log by AmateRS components (data writes, placement actions, membership changes) are encoded as a ClusterCommand and stored in Command::data. The encoding is:

[tag: u8] [json: UTF-8 bytes]

The tag byte allows O(1) dispatch without deserialising the payload.

Variant tags

Tag	Variant
0x01	DataPut
0x02	DataDelete
0x10	PlaceSplit
0x11	PlaceMerge
0x12	PlaceTransfer
0x20	MembershipAdd
0x21	MembershipRemove

State machine boundary

This module is responsible for encoding commands into the Raft log only. The state machine that applies committed PlaceSplit, PlaceMerge, and PlaceTransfer entries — updating the crate::shard::ShardRegistry and migrating data — is a separate concern implemented in future phases.

Enums

ClusterCommand

A typed, serialisable view over the raw Command::data bytes in a Raft log entry.

Constants

TAG_DATA_DELETE

Raft log tag for a KV delete (data plane).

TAG_DATA_PUT

Raft log tag for a KV put (data plane).

TAG_MEMBERSHIP_ADD

Raft log tag for adding a cluster member.

TAG_MEMBERSHIP_REMOVE

Raft log tag for removing a cluster member.

TAG_PLACE_MERGE

Raft log tag for a shard merge action.

TAG_PLACE_SPLIT

Raft log tag for a shard split action.

TAG_PLACE_TRANSFER

Raft log tag for a shard transfer action.